Introduction To Standards Testing Laboratories’ Machinery Division

In
The 1970’s the company that is now Standards Testing Laboratories (STL)
began testing tires for major tire manufacturers located in, and
around, the rubber capital of the World; Akron, Ohio. Indoor laboratory
testing of tires was relatively new at that time. Therefore, of
necessity, STL designed and developed its own tire test equipment. This
new equipment was used in our lab and sold to many of the World’s major
tire manufacturers.

As in-door tire
testing became more prevalent, STL worked with entities such as SAE and
ASTM to develop new test procedures and new equipment.

As
various governments began to issue recommended or required testing
specifications, STL assisted by actively participating in groups,
panels, and organizations to assure that machinery was available to
meet these new test requirements.

STL now
operates one of the largest independent tire and wheel test labs; in
addition to manufacturing tire test machinery for worldwide use.

BUILDING YOUR OWN TIRE AND WHEEL TEST LAB?

For
companies interested in establishing their own complete tire and wheel
testing laboratory, STL can provide our proprietary equipment listed
above. We can also assist with; all other equipment needed for a
quality tire test lab, layout your new lab, start-up your new lab, and
establish and train your personnel in good lab procedures for your
future success.

RADIAL ENDURANCE TIRE AND WHEEL TEST MACHINE

Radial Endurance Machines can be custom designed in a range of drum
sizes (1708 mm, 2000 mm, and 3000 mm are common sizes). Load applied
can range from 5 kg to 100,000 kg depending upon your needs. Speeds can
range from 2 km/hr to as high as 496 km/hr.

All endurance machines are PLC control and have a choice of the
following options: tire rolling radius, tire air pressure control, tire
inside temperature, air blowers for wheel testing, AC or DC motor and
drive, customized levels of safety guarding, choice of hydraulic or
servo-motor loading, spindle brakes, cleats (thumpers) and custom paint
if desired.

The standard STL Radial Endurance Machine includes redundancy circuits
built into the safety E-stop, is made to comply with fire codes NFPA 70
and NFPA 79, uses NEMA 12 panels and has wiring to UL 508A standards.
Additionally, the STL machine uses a forged ring for the drum surface
and dynamically balances high speed drums to meet ISO 1940 G2.5 (the
balance level used for gas and steam turbines). This preserves bearing
life and permits more accurate speed control. The STL radial endurance
machines also include surge protection devices.

STRENGTH TEST and FOOTPRINT MACHINES

Strength
Test (Plunger) and Footprint Machines are available in sizes commonly
used for FMVSS and ECE testing, but are also available for R&D
purposes up to 45,000 kg load. The standard machine will chart a
load/deflection curve. STL can also custom design this type of machine
to permit measurement of static lateral, longitudinal, and torsional
forces if desired.

BEAD UNSEAT MACHINES

Bead
Unseat Machines are specifically designed to comply with individual
international test specifications. The standard STL machine is equipped
with a 19mm, 32mm and 38mm plunger. Our machine is also equipped with
the three newly designed ASTM bead unseat blocks Type 2A, 2B, and 2C.
(The new blocks are designed to work well with new large diameter
custom wheels up to 30”)

Load can be
applied by your choice of hydraulic or servo-motor. The STL machine
design uses mounting cones similar to a standard tire/wheel balancing
machines; multiple wheel adapters are not needed. This results in
considerable time and monetary savings.

DROP IMPACT MACHINE

The
Drop Impact Tester was designed to meet the requirements of SAE J175
wheel tests. We have also found it helpful for certain radial tire
sidewall puncture tests; referred to by STL as “corn stalk puncture
test”.

The machine comes standard with
a 13 degree base. Also available are an SAE spring striker, 30 degree
base, 90 degree base, impact velocity measurement system, and various
tire air systems.

ROTARY FATIGUE WHEEL TEST MACHINE

The
STL Rotary Fatigue Wheel Test Machine is an extremely heavy duty
machine designed for long term use in a harsh environment. This is a
rugged piece of equipment. The machine is controlled by a PLC which
permits step testing, pre-set cycle counter, excessive deflection
shutdown, and variable speeds. Maximum speeds to 750 rpm only.

ROAD HAZARD IMPACT MACHINE by STL

STL participated with SAE in the early test phases of this concept.
Originally for testing wheels, the machine is becoming more popular in
recent years for testing tires. As you can see in the photos above, STL
has developed several alternative striker heads capable of creating
various types of tire failures (the original SAE striker head is shown
in the lower left corner of the accessories photo above).

STL
found the original concept and pendulum design to be too limited.
Developing a more automated lifting method, adding a functional braking
mechanism to limit rebound strikes, and including angle adjustments on
two axes resulted in violating the overall weight and geometry of the
SAE pendulum arm. We believe that a more sophisticated test method is
to accurately measure the speed of each impact and create a simple
formula for each individual machine that properly calculates the impact
energy. There are currently few of these machines in operation and, to
our knowledge, none of them have identical pendulum center of gravity,
center of percussion or moment of inertia. Calculating the properties
of each pendulum and generating the true impact energy for a particular
machine is the proper method for comparing results between the various
machines in operation. Similar to tire rolling resistance machines,
each individual machine is consistent and repetitive but no two
machines have identical pendulum characteristics. Only by targeting the
impact energy can test data from different machines be compared. Of
course, in-house R&D would always be directly comparable since all
tests would be run on the same machine.

The
STL machine is capable of drop angles as great as 176 degrees, striker
angles of +\- 30 degrees, pendulum end weight adjustable from 54
kg to 94 kg, and the STL machine includes your machine’s specific
impact formula programmed into the machine’s laptop computer. Impact
energy will be given for each impact.

ROLLING RESISTANCE MACHINE for PC, LTR, and TBR TIRES

----can be FORCE or TORQUE METHOD ---- or both
FORCE METHOD with heat insulator and servo-motor loading.

One of STL’s 20 year old lab machines for Rolling Resistance testing. TORQUE METHOD ---- still meets all international accuracy standards

STL
does not simply make tire rolling resistance machines; we run tire
rolling resistance machines in our own test lab, every day. We maintain
three (3) RR test stations running almost constantly. STL has two (2)
stations using the Force Method and one (1) station using the Torque
Method. My personal preference is the Torque Method.

To
my knowledge, current regulations for labeling tires exist only in
Europe and Japan. The USA has yet to complete their studies and issue a
rolling resistance regulation.

Europe
has two basic steps to qualifying and labeling tires for sale. First
the tire supplier must qualify a tire line through “type approval”.
Type approval does not take into consideration the difference in
rolling resistance results generated by each individual RR test
machine. For type approval your RR machine does not need to be aligned
to any reference machines.

The
second step to labeling tires for sale in Europe is to have your
machine aligned to one of the 10 or 12 reference machines. The result
will be a formula to be used to correct your machine’s numbers to
reflect what is believed to be the true RR number for a given tire.
This true RR number is thought to be the average generated for that
specific tire if all 10 reference machines where to test that tire. In
essence, Europe has decided that the average RR number generated by all
10 reference machines for a given tire is the true RR number for that
tire. Alignment for European labeling is an expensive procedure.

Bridgestone- Japan has "alignment tires" (2 sizes) manufactured by
Bridgestone and assigned a pre-tested rolling resistance numbers that
can be used to compare your un-aligned machine with the Bridgestone
machine. This will not qualify your machine for European labeling, but
will help in understanding the relevance of your machine's test output
numbers. Currently, these two alignment tires are available at www.jatma.or.jp/english/labeling/contact.html
Find "Related Documents link” at bottom of page, then click on “ARRRT
Basic Condition and Procedures/Request for Quotation"

When
purchasing a tire rolling resistance machine, it is important to
clearly understand that each different RR machine can generate a
different RR number for the same tire. It is the repeatability of your
machine that is of ultimate importance. Your new machine must be
consistent and give repeatable results over long periods of time. This
repeatability is what allows alignment between machines.